Linear motion systems are used to produce precise linear motion along at least one axis of direction. Applications of linear motion systems include any application in which linear motion may be desired. This type of motion is useful in robots, actuators, tables/stages, fiberoptics/photonics alignment and positioning, assembly, machine tools, semiconductor equipment, electronic manufacturing, vision systems, and in many other industrial automation applications. Other applications of linear motion systems include precision medical applications, such as automated digital microscopy which supports a wide range of applications, including cellular imaging and diagnostic instruments, automated inspection and metrology, and DNA sequencing. In microscopy, linear motion systems may be used to control the vertical position of an objective as well as control the position of a specimen in a horizontal plane perpendicular to the axis of an objective.
In a typical linear motion system, a moving carriage can be driven (made to move back and forth) with a variety of motors. These can include, for example, piezo actuators, linear motors, rotary motors and screws, rotary motors and belts, and rotary motors and rack and pinion. Linear motors used in a linear motion system typically include an array of magnets and one or more coils that carry current. The array of magnets may produce a static magnetic field, whereas the coils produce a time-varying magnetic field that depends on the current flowing through the coils. The magnetic field produced by the coils interacts with the static magnetic field to generate a force. For example, in some configurations, the produced force may be linearly proportional to the current and the static magnetic field. The force that is generated can be controlled by controlling the current flowing through the coils. In particular, an electronic motion controller is used to determine the amount of current that should flow through the coils to produce the intended motion. An electronic drive can receive logic-level commands from the electronic controller and translate those commands into the currents that flow through the one or more coils.
Generally, linear motion systems include a stage featuring a stationary base and a moving carriage. In a linear motion system including a linear motor, current flows through the one or more coils of the linear motor. The moving carriage can move relative to the stationary base along a linear axis. To guide the moving carriage along a straight line, the stage can include linear guideways. In addition, the linear motion stage may include an encoder, which can measure the position of the moving carriage relative to the stationary base. A position signal from the encoder may be provided to the controller to assist the controller in determining the correct amount of current to be supplied by the drive to the one or more coils to achieve a desired position. Such linear motors, which use position feedback to control motion and final position, are referred to as linear servomotors.
Traditional linear motion systems suffer from a number of problems. For example, interface cables must be provided that connect the drive and coils. Such interface cables increase the cost of materials of a linear motion system as well as the cost of assembly. This setup requires interface cables, often containing up to fifteen conductors per cable. This arrangement also requires special routing features for the cabling to exit the system to the drive. In addition, the controller, drive, and interface cables increase the weight and size of the linear motion system.
Traditional linear motion systems require multiple components (i.e., motor, encoder, drive, etc.) to be assembled in a potentially labor intensive process. Connections are typically made using expensive cabling and connectors. This cabling carries sensitive, critical signals (i.e. encoder feedback) and high motor currents.
Two linear motion stages may be combined to form a dual-axis linear motion system. For example, a first linear motion stage may provide motion along an x axis, whereas a second linear motion stage may provide motion along a y axis that is perpendicular to the x axis. Dual-axis linear motion stages are typically formed from at least three plates, which are usually metal. In particular, a typical dual-axis linear motion system includes a base plate, a top plate, and a third center plate that separates the base plate and top plate.
In addition to the above problems, two-axis linear motion systems suffer from additional problems. For example, the presence of the third center plate adds bulk, weight, and cost to the system.
It is, therefore, an object of the present disclosure to overcome the above problems and others by providing a linear motion system with integrated components such as controller, drive, motor and encoder. In addition, it is an object of the present disclosure to overcome the above problems by providing a miniaturized stage. Furthermore, it is an object of the present disclosure to overcome the above problems by providing a motion system that is more cost-effective to manufacture.